Validação de um dispositivo não-invasivo e não-destrutivo para avaliação do estado de maturação das uvas

• Author(s): Graça, João Nuno Duarte
• Date: 2014
• Persistent ID: http://hdl.handle.net/10400.5/6808
• Origin: Repositório da UTL
• Subject(s): grapevine; brix; titratable acidity; anthocyanins; reflectance; fluorescence
• Document Type: Master thesis
• Language: Portuguese
• Advisor(s): Lopes, Carlos Manuel Antunes
• Contributor(s): Repositório da Universidade de Lisboa

Description

Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia / Faculdade de Ciências. Universidade do Porto

In this work, WinePen validation procedures were applied in order to verify the robustness of the device in the field and the models used to estimate the parameters Brix, Titratable acidity and Anthocyanins. This device’s operating system is based on reflectance and fluorescence. This validation was held in 2013, on vineyards with white and red varieties, in the Superior Institute of Agronomy, situated in the Wine Region of Lisbon. For WinePen validations, 25 berries of each variety were measured, under different conditions (laboratory and field) in order to verify the light effect on measurements. The berries were first analyzed by WinePen and afterwards examined in the laboratory. In order to select the best models, the fitting quality of the observed values was evaluated using the following deviance measures: determination coefficient (R2), mean absolute error (MAE); root mean square error (RMSE). High and significant correlations for Brix (0.93 to 0.96) and for titratable acidity (0.86 to 0.96) were observed for different types of environment (laboratory and field) and for different varieties (whites and reds). However, the anthocyanins parameter observed lower and less significant correlations (0.70) in both reading conditions. Thereby, the results obtained demonstrate the reliability of measurements performed by WinePen for different varieties and environments